U.S. patent number 5,040,046 [Application Number 07/594,366] was granted by the patent office on 1991-08-13 for process for forming highly conformal dielectric coatings in the manufacture of integrated circuits and product produced thereby.
This patent grant is currently assigned to Micron Technology, Inc.. Invention is credited to Navjot Chhabra, Rodney D. Morgan, Eric A. Powell.
United States Patent |
5,040,046 |
Chhabra , et al. |
August 13, 1991 |
Process for forming highly conformal dielectric coatings in the
manufacture of integrated circuits and product produced thereby
Abstract
A process for forming silicon dioxide, SiO.sub.2, or silicon
nitride, Si.sub.3 N.sub.4, layers on selected substrates which
includes reacting diethylsilane, C.sub.4 H.sub.12 Si, with a
selected oxygen-containing compound or nitrogen-containing compound
in a plasma enhanced chemical vapor deposition (PECVD) chamber. The
conformality of the coatings thus formed is in the range of 85% to
98%. The diethylsilane liquid source for the associated gas flow
processing system may be maintained and operated at a source
temperature as low as room temperature.
Inventors: |
Chhabra; Navjot (Boise, ID),
Powell; Eric A. (Boise, ID), Morgan; Rodney D. (Boise,
ID) |
Assignee: |
Micron Technology, Inc. (Boise,
ID)
|
Family
ID: |
24378582 |
Appl.
No.: |
07/594,366 |
Filed: |
October 9, 1990 |
Current U.S.
Class: |
257/635; 427/579;
428/447; 438/789; 427/255.37; 427/255.394; 438/793 |
Current CPC
Class: |
C23C
16/45561 (20130101); C23C 16/402 (20130101); C23C
16/45512 (20130101); C23C 16/345 (20130101); Y10T
428/31663 (20150401) |
Current International
Class: |
C23C
16/40 (20060101); C23C 16/34 (20060101); C23C
16/44 (20060101); C23C 016/50 () |
Field of
Search: |
;427/39,255.2,255.3,38
;437/235,238,241,243 ;428/447 ;357/54 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Beck; Shrive
Assistant Examiner: Owens; Terry J.
Attorney, Agent or Firm: Bethurum; William J.
Claims
We claim:
1. A process for forming inorganic dielectric layers on
semiconductor substrates which comprises exposing said substrates
to a plasma reaction of diethylsilane, C.sub.4 H.sub.12 Si, and a
reactive element-containing compound at a predetermined temperature
to deposit said dielectric layers which contain said reactive
element on the exposed surfaces of said semiconductor
substrates.
2. The process defined in claim 1 wherein said semiconductor
substrates are silicon and said reactive element-containing
compound is selected from the group consisting of oxygen, O.sub.2,
nitrous oxide, N.sub.2 O, and ammonia, NH.sub.3, whereby inorganic
dielectric layers of silicon dioxide, SiO.sub.2, or silicon
nitride, Si.sub.3 N.sub.4, are deposited on said silicon substrates
with a conformality of 85% or greater.
3. The process defined in claim 2 wherein said predetermined
temperature is in the range of 325.degree. C. through 450.degree.
C.
4. The process defined in claim 3 wherein said diethylsilane,
C.sub.12 H.sub.4 Si, is maintained at a source temperature in the
range of 25.degree. C. through 35.degree. C.
5. A process for depositing silicon dioxide or silicon nitride
insulating layers on semiconductor substrates which comprises the
steps of:
a. inserting a semiconductor substrate between reaction electrodes
within a plasma reaction chamber,
b. introducing diethylsilane, C.sub.4 H.sub.12 Si, and either a
selected oxygen-containing or nitrogen-containing compound into
said plasma reaction chamber while maintaining said diethylsilane
at a source temperature between room temperature of about
25.degree. C. and a temperature of about 35.degree. C., and
c. creating a plasma reaction between said diethylsilane and said
oxygen-containing or nitrogen-containing compound to thereby
deposit either an oxide coating or a nitride coating on a surface
of said semiconductor substrate which is exposed to said plasma
reaction.
6. The process defined in claim 5 wherein said nitrogen containing
compound is ammonia, NH.sub.3, and said oxygen containing compound
is selected from the group consisting of oxygen, O.sub.2, and
nitrous oxide, N.sub.2 O.
7. The process defined in claim 6 wherein the temperature at the
source of said diethylsilane is maintained at a level in the range
of between about 25.degree. C. to about 35.degree. C.
8. The process defined in claim 6 wherein diethylsilane, C.sub.4
H.sub.12 Si, and oxygen, O.sub.2, are reacted in said plasma
reaction chamber at a predetermined temperature to form silicone
dioxide, SiO.sub.2, carbon dioxide CO.sub.2, and water, H.sub.2
O.
9. The process defined in claim 6 wherein diethylsilane and N.sub.2
O are reacted in a plasma reaction chamber at a predetermined
temperature to form SiO.sub.2 and CO.sub.2 and H.sub.2 O and
N.sub.2.
10. The process defined in claim 6 wherein diethylsilane and
NH.sub.3 are reacted in said plasma reaction chamber at a
predetermined temperature to form Si.sub.3 N.sub.4 and carbon
compounds.
11. An integrated circuit having highly conformal layers of either
silicon dioxide, SiO.sub.2, or silicon nitride, Si.sub.3 N.sub.4,
formed on the surface of a silicon substrate, said conformal layers
being formed to a conformality in the range of 85%-98% by the
process of:
a. inserting a silicon substrate between reaction electrodes within
a plasma reaction chamber,
b. introducing diethylsilane and either a selected
oxygen-containing or nitrogen-containing compound into said plasma
reaction chamber, said nitrogen containing compound being ammonia,
NH.sub.3, and said oxygen containing compound being selected from
the group consisting of oxygen, O.sub.2, and nitrous oxide, N.sub.2
O, and
c. creating a plasma reaction between said diethylsilane and said
selected oxygen-containing or nitrogen-containing compound at a
predetermined temperature to thereby deposit either an oxide
coating or a nitride coating on a surface of said silicon substrate
which is exposed to said plasma reaction.
Description
TECHNICAL FIELD
This invention relates generally to processes for forming
multiple-use dielectric coatings in the manufacture of very large
scale integrated circuits, such as dynamic random access memories
(DRAMs). These coatings may be used for semiconductor surface
passivation and protection, diffusion masks and barrier layers,
spacers for device separation, and the like. More particularly,
this invention is directed to such processes for forming highly
conformal dielectric coatings of improved reliability, quality and
density using relatively low temperature semiconductor wafer
processing.
BACKGROUND ART
During the manufacture of various types of monolithic integrated
circuits (ICs) such as high density DRAMs having several thousand
transistors fabricated in a single chip of silicon, there are many
stages in the multi-level layer wafer processing sequence where it
is desirable to provide highly conformal coatings of a selected
dielectric insulating material such as silicon dioxide, SiO.sub.2,
or silicon nitride, Si.sub.3 N.sub.4. That is, it is desirable to
deposit these insulating coatings so that they precisely replicate
the geometry of the layers upon which they are formed. This feature
ensures that electrical shorts through these very thin dielectric
layers are prevented and it further ensures that the packing
density and general reliability of the integrated circuit being
fabricated are maximized.
Over the years, there have been many different types of thermal
oxidation processes, vapor deposition processes and plasma
deposition processes used to form oxides, nitrides, carbides, and
other dielectric coatings in the manufacture of integrated
circuits. Of these processes, there are two types in particular
which have been used in recent years in the manufacture of high
density DRAMs. The first of these processes is a low pressure
chemical vapor deposition (LPCVD) process which may use, for
example, tetraethylorthosilicate (TEOS) or diethylsilane (DES) as
the silicon-containing reactive compound to form either oxide or
nitride coatings on selected substrates. However, there are many
attendant disadvantages associated with using low pressure chemical
vapor deposition systems, and among these include the fact that
these LPCVD systems have to be heated up to temperatures in the
range of 450.degree. to 500.degree. C. in order to suitably
generate the LPCVD chemical reaction necessary to dissociate the
silicon or nitrogen containing compound and deposit the silicon
dioxide or silicon nitride layer on a selected substrate.
In addition, the liquid delivery systems for the LPCVD apparatus
are difficult to operate and maintain in order to produce reactant
gases in the LPCVD deposition chamber, and the dielectric layer
deposition rates for these LPCVD systems are difficult to control.
Furthermore, these LPCVD systems are difficult to clean, and the
device reliability of the semiconductor devices thus produced has
not always been acceptable. For example, frequently hillocks and
precipitates are produced in aluminum conductive layers over which
the silicon dioxide or silicon nitride protective layers are
formed.
More recently, plasma enhanced chemical vapor deposition (PECVD)
systems have come to replace some of the older LPCVD systems, and
generally speaking, PECVD systems have come to be more of a favored
choice over LPCVD systems, even though LPCVD systems are still
widely used for a variety of materials deposition processes. For
approximately the past five years, silane, SiH.sub.4, has been used
as the silicon-containing reactive gas in these PECVD systems.
However, the problem and disadvantage of using silane as a reactive
gas in these PECVD systems is that it is impossible to achieve a
conformality of greater than about sixty percent (60%) for the
inorganic insulating layers thus formed.
To improve this conformality in the inorganic dielectric layers
produced by these PECVD systems, tetraethylorthosilicate (TEOS) has
been tried as a possible candidate and suitable reactant gas in
PECVD systems for forming silicon-containing dielectric layers on
selected substrates. However, there are several distinct
disadvantages of using TEOS as the silicon containing compound in
PECVD systems. For example, TEOS has a very low vapor pressure and
thus must be heated up to a source temperature of greater than
50.degree. C. to produce vapors from a TEOS source and suitable for
transporting these vapors from a TEOS source and into a PECVD
reaction chamber. This requirement in turn means that special mass
flow controllers must be used in these TEOS systems. Additionally,
the TEOS gas delivery lines as well as the mass flow controllers
must be maintained at a predetermined minimum elevated temperature
in order to prevent condensation in the gas flow lines and its
associated damage to the chemical processing equipment which can
produce significant maintenance problems. Furthermore, the use of
TEOS in PECVD systems has been found to produce undesirable
variations in dielectric layer deposition rates on selected
substrates.
DISCLOSURE OF INVENTION
In accordance with the present invention, it has been discovered
that the use of diethylsilane (DES) as the silicon containing
reactant gas in a plasma enhanced chemical vapor deposition system
affords the maximum number of process and device reliability
advantages when compared to any other known prior art low pressure
chemical vapor deposition system or to any other known plasma
enhanced chemical vapor deposition system used in forming either
oxides or nitrides on the surfaces of selected substrates. Among
these many advantages include the ability to produce higher quality
oxide and nitride layers of higher densities and at higher layer
deposition rates and with a greater layer thickness uniformity than
were heretofore achievable. Simultaneously, these advantages are
achieved using a cleaner, lower cost, and easier-to-operate
reactant gas flow system for feeding the PECVD chamber than was
heretofore available.
In addition to the above very significant advantages which are
afforded by practicing the present invention, the present invention
provides the further advantage of being practicable at a relatively
low temperature. This feature results from the fact that the vapor
pressure of diethylsilane (DES) is, for example, approximately ten
(10) times higher than that of tetraethylorthosilicate (TEOS).
Thus, DES vapors can be driven off of the DES liquid source at
almost room temperature or perhaps only slightly elevated therefrom
(e.g. 35.degree. C.) to produce highly dense and highly conformal
layers of silicon dioxide and silicon nitride having a conformality
typically in the range of 85 to 98%. This low temperature gas flow
operation greatly minimizes maintenance and repair problems within
the gas flow delivery system and enhances overall reliability of
the semiconductor devices thus produced. This process has the
further advantage of improving the uniformity and consistency of
dielectric layer deposition rates within the PECVD chamber.
These silicon dioxide and silicon nitride layers are useful in a
wide range of applications in the manufacture of many different
types of integrated circuits. For example, these applications
include the use of these materials as protective layers for
integrated circuit conductors, protective and passivating layers
for semiconductor surfaces and PN junctions formed thereon, spacers
for use on word lines and bit or digit lines of random access
memories, and as diffusion masks for determining the P or N-type
conductivity profiles in semiconductor substrates. Furthermore, it
has also been discovered that the process according to the present
invention is capable of minimizing hillocks and precipitates which
have heretofore occurred at the surfaces of conductive strips or
layers which are covered and protected by the oxide and nitride
layers thus formed. Moreover, it has further been discovered that
not only can highly conformal insulating films very close to 100%
conformality be formed using the present process, but the resultant
stress of these insulating films can be both minimized and made
variable to suit a particular device application as will be
described in more detail below.
The above many advantages and attendant novel features of this
invention are achieved by the provision of a plasma enhanced
chemical vapor deposition process of the type described which
includes the steps of:
a. providing a selected substrate between reactive electrodes
within a plasma reaction chamber,
b. introducing diethylsilane and a selected oxygen-containing
compound or a selected nitrogen-containing compound into the plasma
reaction chamber at a relatively low source temperature at or only
slightly greater than room temperature, and
c. creating a plasma reaction within the plasma reaction chamber
and between the diethylsilane and either the selected
oxygen-containing or the nitrogen-containing compound to thereby
deposit either an oxide coating or a nitride coating on the surface
of the substrate which is exposed to the plasma reaction. In this
manner, low temperature gas flow processing results in improved
reliability and operational characteristics of the gas flow PECVD
processing system used as well as the semiconductor devices and
integrated circuits produced thereby.
The present invention described briefly above, together with its
attendant advantages and novel features, will become better
understood from the following description of the accompanying
drawings
BRIEF DESCRIPTION OF THE DRAWING
FIG. 1 is a schematic process flow diagram of one embodiment of
this invention illustrating a gas delivery system leading into a
plasma enhanced chemical vapor deposition reaction chamber and
useful for effectively carrying out the novel processes claimed
herein.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring now to FIG. 1, a source 10 of diethylsilane (DES),
C.sub.4 H.sub.12 Si, is provided in a conventional bubbler chamber
12 having a heater coil 14 therein for heating the diethylsilane
source 10 to a temperature of about 35.degree. C., or only slightly
higher than room temperature of typically about 25.degree. C.
Diethylsilane, C.sub.4 H.sub.12 Si, is commercially available in
the preferable semiconductor grade from the Schumacker Corporation
in Carlsbad, Calif. Vapors from the liquid diethylsilane source 10
pass upwardly through the adjoining gas flow line 16 to a pressure
regulator 18. The pressure in the gas flow line 16 will vary
slightly with the variation of DES liquid levels in the ampoule 12.
The pressure regulator 18 includes an input valve V1 which is
operative to maintain the input pressure to the regulator 18 at a
value of about -14 inches of mercury, Hg, and an output valve V2
operates to maintain the output pressure from the regulator 18 and
in the gas flow line 20 at a pressure of about --18 inches of
mercury. The pressure regulator is further connected as shown by
way of another gas feed line 22 to a source 24 of N.sub.2 purge gas
used in purging the system prior to start up and is also used to
flush out the system when the ampoule 12 is being replaced with a
new ampoule. Both of the gas feed lines 16 and 22 are provided with
shut off valves 17 and 19, respectively, which may be used at any
time to both start up and shut down the system operation.
The diethylsilane vapors passing down the gas flow line 20 enter a
NUPRO type of air activated shut-off valve 26 whose output port is
connected by way of the gas feed line 28 to a first mass flow
controller 30. The output port of the mass flow controller 30 is in
turn connected by way of an additional gas feed line 32 into a
first manifold 34 wherein the diethylsilane vapors are combined and
mixed with additional nitrogen gases from the N.sub.2 source 38 to
provide a good uniform gas mixture before exiting the output gas
feed line 36.
An additional source of nitrogen gas is provided as indicated at
the N.sub.2 gas reservoir 38 which is connected by way of a gas
feed line 40 and into a second NUPRO type of air activated shut-off
valve 42. The air activated shut-off valve is in turn connected to
a second mass flow controller 44 whose output gas feed line 46 is
connected as a second input to the first manifold 34.
A source of either ammonia, NH.sub.3, oxygen, O.sub.2, or nitrous
oxide, N.sub.2 O, as indicated at the gas reservoir 48 is connected
by way of its output gas feed line 50 to a third NUPRO type of air
activated shut-off valve 52. The NUPRO valve 52 is in turn
connected by way of its output gas feed line 54 to a third mass
flow controller 56 which serves to control the gas flow rate of
either ammonia, oxygen or nitrous oxide by way of output feed line
56 into a second manifold 58. All of the above identified mass flow
controllers 30, 44, and 56 are preferably of the electronic type
wherein a variable set point may be established to provide a
constant chosen gas flow rate and to automatically compensate for
external parameter variations, such as variations in temperature
and variations in pressures in the various feed lines of the
system. The manifolds 34 and 60 which are fed by the above
identified mass flow controllers are used simply to provide good
premixing of the various combined gases, and the hydrides in the
gas feed line 36 are separated from the oxygen containing compounds
and ammonia, NH.sub.3, until passing through the feed line 64 and
into the premixing chamber 66. This is done primarily as a safety
precaution as is known for these types of PECVD gas flow
systems.
The particular selected reactant gas (NH.sub.3, O.sub.2 or N.sub.2
O) indicated at source 48 is then passed through an output gas feed
line 62 exiting from the second manifold 60 and is then combined in
the common gas feed line 64 with the diethylsilane and nitrogen
vapors received from the gas feed line 36. This gaseous mixture is
then fed by way of the common gas feed line 64 into a premixing
chamber 66 positioned directly adjacent to the plasma enhanced
chemical vapor deposition chamber 68.
The PECVD chamber 68 includes a cathode electrode 70 and an anode
electrode 72 spaced apart therein, with each electrode connected to
a separate RF voltage source 74 and 76 as shown. One suitable PECVD
reaction chamber 68 useful in carrying out the above described
process is available from the Novellus Corporation of San Jose,
Calif. and sold under the trade name CONCEPT I. This type of PECVD
plasma reaction chamber will also typically include a pump and
exhaust feed line 78 which is connected to the PECVD chamber 68 to
provide the necessary pumping to establish the necessary partial
vacuum conditions therein during PECVD operation and to provide the
necessary gas exhaust line 78 therefor used to flush out the system
after a wafer processing operation has been completed.
In the normal operation, a silicon wafer 80 will be disposed on the
upper surface of the anode electrode 72 as shown, and may have been
processed to various stages toward completion of the ultimate or
complete integrated circuit being fabricated. For example, the
wafer 80 may have been processed to the stage where conductive
interconnect strips have been photodefined and disposed and
interconnected on the wafer surface and are now ready to receive a
protective inorganic dielectric coating of either SiO.sub.2 or
Si.sub.3 N.sub.4, or both, thereon in accordance with the examples
given below.
As previously indicated, the power ratios received from the high
frequency RF source 74 and from the low frequency RF source 76 may
be varied in order to vary the stress of the deposited dielectric
layer from a highly tensile state to a highly compressive state.
The high frequency RF source is typically operated at 13.56
megahertz and the low frequency RF source is typically operated
between 100-400 kilohertz. The high frequency RF source is
connected as shown through an anti-reflection impedance matching
network 82 which prevents high frequency RF power from being
reflected back into the RF source 74. Such an impedance matching
network is not required for the low frequency RF source 76. As an
example, the total RF power applied to the PECVD chamber may be
2200 watts, with 800 watts being applied from the high frequency RF
source 74 and 400 watts being applied from the low frequency RF
source 76. As a general rule and making certain other conventional
assumptions and assuming certain constant values for the particular
layers and other components of the wafer 80 at a particular stage
in its processing sequence, an increase in high frequency power and
a corresponding decrease in low frequency power will increase the
compressive stresses in the deposited layers in dynes per
centimeter squared. Conversely, a reversal of these low frequency
to high frequency power ratios will serve to increase the tensile
forces in the deposited layers.
Accordingly, the use of diethylsilane in combination with a plasma
enhanced chemical vapor deposition reaction of the type illustrated
in FIG. 1 and further in combination with either a
nitrogen-containing or oxygen-containing gas source is capable of
producing, respectively, very dense, uniform and consistent layers
of either silicon nitride or silicon dioxide on a silicon substrate
80 at very uniform layer deposition rates. In addition, this novel
system and deposition process provides many advantages as
previously described relative to any other known low pressure
chemical vapor deposition (LPCVD) process or plasma enhanced
chemical vapor deposition (PECVD) process used for forming these
same dielectric layers on silicon substrates.
The following Example 1 provides processing parameters useful in
accordance with the present invention for forming silicon dioxide
coatings using oxygen as the oxygen-containing gas. Example 2 below
provides processing parameters for forming silicon dioxide,
SiO.sub.2, coatings using nitrous oxide, N.sub.2 O, as the oxygen
containing gas. Example 3 below provides the necessary process
parameters for forming a dielectric layer of silicon nitride,
Si.sub.3 N.sub.4, on a silicon substrate using ammonia, NH.sub.3,
as the nitrogen containing gaseous compound.
EXAMPLE 1
Diethylsilane, C.sub.4 H.sub.12 Si, was heated in the bubbler
ampoule 12 to a temperature of about 35.degree. C. and then passed
through the gas feed line 20 at a pressure of approximately 20
inches of mercury and then through the mass flow controller 30 at a
gas flow rate of 240 standard cubic centimeters per minute (sccm)
into the first manifold 34. Oxygen was passed from the gas source
48 and at a pressure of approximately 35 psi in the gas feed line
54 and then through the mass flow controller 56 at a gas flow rate
of about 8 liters per minute. The nitrogen source 38 was not used
for this SiO.sub.2 deposition run. The PECVD chamber 68 was pumped
down to a pressure of about 1.8 Torr and heated to about
350.degree. C. The high frequency RF power in the PECVD chamber 68
was set to 600 watts and the low frequency RF power therein was set
to 600 watts during the deposition of approximately 6560 angstroms
of silicon dioxide on a silicon substrate 80 which was disposed as
shown on the anode 72. This SiO.sub.2 deposition was carried out in
a time of approximately seventy (70) seconds and in accordance with
the following expression: ##STR1##
EXAMPLE 2
Diethylsilane, C.sub.4 H.sub.12 Si, was heated in the bubbler 12 to
a temperature of about 35.degree. C. and passed through the gas
feed line 20 at approximately -20 inches of mercury and through the
mass flow controller 30 at 240 standard cubic centimeters per
minute (sccm) into the first manifold 34. Nitrous oxide, N.sub.2 O,
was passed from the source 48 at a pressure of 35 psi in the gas
feed line 54 and then through the mass flow controller 56 at a gas
flow rate of between 7 and 8 liters per minute and then into the
second manifold 60. The DES vapors exiting the first manifold 34 by
way of gas feed line 36 were then mixed with the N.sub.2 O vapors
received from the second manifold 60 in the common gas feed line 64
leading into the premixing chamber 66. The nitrogen source 38 again
was not used in this SiO.sub.2 deposition run. The PECVD chamber 68
was pumped down to a pressure of about 1.9 Torr and heated to an
elevated temperature of about 350.degree. C. The high frequency RF
power for the PECVD chamber 68 was set to 500 watts and the low
frequency RF power therein was set to 800 watts during the
deposition of 5700 angstroms of SiO.sub.2 on a silicon substrate 80
disposed on the anode 72. This deposition was carried out in a time
of about seventy (70) seconds in accordance with the following
expression: ##STR2##
EXAMPLE 3
Diethylsilane, C.sub.4 H.sub.12 Si was heated to a temperature of
about 35.degree. C. in the bubbler 12 and passed through the gas
feed line 20 at approximately -20 inches of mercury and then
through the mass flow controller 30 at 150 standard cubic
centimeters per minute (sccm) into the first manifold 34. Ammonia,
NH.sub.3, was passed from the gas source 48 and through the mass
flow controller 56 at a gas flow rate of about 2 liters per minute
into the second manifold 60. In addition, and in order to improve
the uniformity of the silicon nitride film being deposited,
nitrogen was passed from the auxiliary N.sub.2 source 38, through
the mass flow controller 44 and through the gas feed line 46 at a
gas flow rate of approximately 2 liters per minute into the first
manifold 34 where the nitrogen was mixed with the diethylsilane
received from the gas feed line 32. The PECVD chamber 68 was pumped
down to a pressure of about 3.0 Torr and heated to about
400.degree. C. before applying a high frequency RF power of 500
watts and a low frequency RF power of 800 watts to the cathode 70
and anode 72, respectively, in the PECVD chamber 68 as previously
described. During this process deposition, approximately 4200
angstroms of silicon nitride were deposited on a silicon substrate
80 disposed on the PECVD anode 72 in a time of about 175 seconds.
This silicon nitride deposition was carried out in accordance with
the following expression: ##STR3##
Various modifications may be made in and to the above described
embodiments without departing from the spirit and scope of this
invention. For example, the present invention is limited neither by
the specific gas flow processing system illustrated in FIG. 1
herein nor by the specific processing parameters given in the above
examples. Accordingly, obvious process flow system design and
process modifications used therein may be made to the above
described inorganic layer deposition processes and examples of
dielectric layers formed without departing from the scope of the
present invention.
It is also within the scope of the present invention and the claims
appended hereto to deposit materials other than those specifically
described above, such as epitaxial silicon, silicon carbide and
silicon oxy-nitride, Si.sub.x O.sub.y N.sub.z, phosphorus silicate
glass (PSG) and borophosphorus silicate glass (BSG) using
diethylsilane and by modifying the reactant gas sources in FIG. 1
in a controlled manner by those skilled in the art. In addition,
for all of the above described processes, it is possible to operate
the DES source 10 at room temperature or 25.degree. C. and thereby
eliminate the heating element 14 as previously described. That is,
the various vapor and gas delivery lines described above and
located between the DES source 10 and the PECVD chamber are
relatively short, so that it is possible to obtain an adequate
vapor flow rate in the delivery lines of this system at room
temperature.
It is further possible to operate the PECVD chamber 68 in all of
the above examples within a wide temperature range of between
325.degree. C. and 450.degree. C. as a matter of choice and
depending upon whether higher temperatures in the range of
400.degree. C. or greater would be unduly degrading to the
semiconductor structures being processed. Accordingly, these and
other process and materials variations are clearly within the scope
of the following appended claims.
* * * * *